基于曲率分布控制的叶型前缘设计方法

为了实现对压气机叶片的优化，提出了一种基于曲率分布控制的前缘造型方法，实现了对叶型前缘曲率的直接、精确控制。将该造型方法应用于某工业级压气机的可控扩散叶型（CDA）上，通过数值仿真方法计算了叶型在设计来流马赫数下的全攻角工况性能。结果显示增加前缘曲率能有效拓宽许用攻角范围，减小尖峰扩散因子，在相同攻角下能削弱前缘吸力峰，抑制甚至消除前缘分离泡，避免提前转捩的发生。同时，调整曲率分布使其在靠近前缘点处尽可能"饱满"、减缓曲率下降速度，也有同样的效果。理论分析发现前缘曲率通过调整静压分布影响边界层发展起始流态，从而影响叶型性能。设计前缘几何形状时需要确保曲率连续性，调整曲率分布以减小前缘吸力峰的强度，避免分离诱导转捩的出现。

Leading edge design method based on curvature distribution control

To optimize the aerodynamic performance of compressor blades, we propose a leading edge design method based on curvature distribution control, realizing direct and precise control of the leading edge curvature. This design method is applied to the Controlled Diffusion Airfoil (CDA) of an industrial compressor, and the performance of the airfoil with the designed Mach number at all incidences is calculated by the numerical simulation method. The results show that increasing the curvature of the leading edge can effectively broaden the allowable incidence range and reduce the peak diffusion factor. At the same angle of attack, the optimized airfoil can weaken the leading edge suction peak, suppress or even eliminate the separation bubble, and avoid the occurrence of early transition. Meanwhile, adjusting the curvature distribution to make it as "full" as possible and slowing down the decrease rate of curvature in the vicinity of the leading edge point can achieve the same effect. Theoretical analysis reveals that the curvature of the leading edge affects the initial flow pattern of the boundary layer by adjusting the static pressure distribution, therefore affecting the performance of the blade as well. In designing the leading edge geometry, it is necessary to ensure the curvature continuity, adjust the curvature distribution to reduce the strength of the leading edge suction peak, thus avoiding the occurrence of separation-induced transition.